Fan



April 1935. w. BALLENTINE 1,998,184

FAN

Filed March 15, 1954 2 Sheets-Sheet l April 16, 1935.

E. w. BALLENTINE 1,998,184

FAN

Filed March 15, 1934 2 Sheets-Sheet 2 fizy/ 552 am- Zia.

- cold air inlet of a furnace (not shown).

Patented Apr. 16, 1935 UNITED STATES FAN Earle W. Ballentine, Chicago,

Solar Industries, Inc., tion of Illinois Ill., assignor to Chicago,111., a corpora- Application March 15, 1934, Serial No. 715,786

4 Claims.

This invention relates to improvements in fans and, more especially, apressure fan for furnace application.

Among the features of my invention is the provision of such a fan simplein construction and operation which can be manufactured and operated atrelatively low cost. My improved fan is practically noiseless and has ahigh degree of efiiciency.

Another feature of my invention is the provision of a fan of thecharacter described that can be used for furnace application and whichwill offer a minimum resistance to free gravity circulation when the fanis not operating. My improved fan is also substantially non-loading sothat practically constant power is required at all deliveries. Myimproved fan is especially designed to operate vertically so that theair thrust counterbalances the weight of the fan and the shaft, so thata rotating system with minimum friction resistance is the result.

I have found that for a disc fan to efliciently produce pressure, it isnecessary that the area of the blades approximate the face area of thefan. This consideration is limited only by the fact that it is necessaryto have sufficient port area to give the necessary volumetric capacity.My improved fan has only two blades which, for example, may beapproximately 22" in diameter and revolve at 750 R. P. M. Thiscombination produces substantially no air waves of a frequency exceeding25 beats per second and, therefore, the operation is substantiallynoiseless.

I also prefer to make the pitch of the blades uniform in order to give auniform rate of displacement and, accordingly, a uniform pressure.

Other features and advantages of my invention will appear more fully asI proceed with my specification.

In that form of device embodying the features of my invention shown inthe accompanying drawings- Figure l is a view in perspective; Fig. 2 isa diagrammatic view showing the shape of one of the blades; Fig. 3 is atop plan view of the fan; Fig. 4 is a view in side elevation; Fig. 5 isa diagrammatic view showing the dimensions and angle of inclination ofthe blades.

As shown in the drawings, the fan may be mounted in a suitable andrectangular casing ID to which is connected a boot ll leading to theAbove the casing l 0 is a filter casing l2 designed to hold suitablefilters l3 forming no part of the present invention. I4 indicates thecold air inlet. I5 indicates an orifice plate which is provided with acircular orifice l 6 which may, for example, be 24" in diameter.

I 1 indicates a spider supported on suitable legs I 8 carrying thebearing member IS in which is supported the shaft 20. This shaft maycarry a belt wheel 2| on its lower end adapted to be driven by the belt22 from the motor 23. The upper end of the shaft is provided with a fanhub 24 carrying the inclined flanges 25, 25 to which the blades 26, 26are attached.

In the practice of my invention, the size, shape, proportions,dimensions and inclinations of the blades of the fan are important and,consequently, I shall describe these in detail, it being understood thatboth blades are similar. In Fig. 2 I have shown a circle 21, thediameter of which is the diameter of the fan. In this circle I haveshown one of the fan blades 26 laid fiat. It will be seen that the widthof this blade, as indicated by the line 26 is substantially uniform andis substantially of the diameter of the fan. In Fig. 5, I have showndiagrammatically a side view of one of the blades in order to indicateits inclination. In this view the diameter of the fan is indicated bythe line 26'. As stated above, the width of the blade is 75% of thediameter. When the blade is inclined as shown in Fig. 5 at an angle of28 to the horizontal, its projection on the diameter will extend fromthe point A to the point B and this distance is substantially 65% of thediameter. I have found that very good results are obtained when theblades are made and inclined as shown in Figs. 2, 3 and 4, that is, whenthe blade has such inclination and width that its projection issubstantially 65% of the fan diameter. In other words, I have found thatwith less inclination the blade ought to be made narrower, and viceversa, in order to keep the projection between 40% and of the fandiameter. As shown, such projection is 65% of the fan diameter and, asstated, .I have found this to give good results. As stated above also,the width of the blade as shown is 75% of the fan diameter. I have foundthis to give good results, although such width may vary from 50% to ofthe fan diameter. Also, as stated, I have found the inclination of 28 togive good results, although it appears that such angle may vary from 15to 45.

It will be noticed also that I prefer to curve the ends of the blades.This is shown in Fig. 2 where the curvature of the end is indicated by30, such curvature being the arc of a circle.- Such the spirit and scopeof Y prior art.

curved ends'give the maximum blade area in a given diameter. r 7 while 1have shown and described certain embodiments of my invention, it is tobe understood that it is capable of many modifications. Changes,therefore, in the construction and arrangement may be made withoutdeparting from my invention as disclosed in the appended claims, inwhich it is my intention to claim all novelty inherent in 1117 inventionas broadly as permissible, in view of thewhatlclaimasnemanddesiretosecureby Letters Patent, is:

1. In combination with a casing, 'a rotary air fan therein adapted tomove air in said casing against static pressure therein, said ianincluding a hub and only two similar blades, said blades oppositelyarranged and inclined with respect to said hub and attached thereto,each blade having a radial length substantially equal to halt the iantherein adapted -to. .move air in said casing.

against static pressure therein,"said ian including a hub and only twosimilar blades, said blades oppositely arranged and inclined withrespect to said hub and attached thereto, each blade having a radiallength substantially equal to halt the distance between the tips of theblades and a substantially uniform width throughout its length 3. Adevice as claimed in claim 1, in which the inclination of the bladeswith respect to the plane of rotation is less than 4. A device asclaimed in claim 2, in which the inclination of the blades with respectto the plane oi rotation is less than 45".

EARLE w. BALLENTINE.

of substantially of its radial length.

